Ecosystem

N increment over this period was estimated at 20 kg ha−1 yr−1, with 13 kg ha−1 yr−1 in vegetation, 15 kg ha−1 yr−1 in forest floor, and −8 kg ha−1 yr−1 in soils. The observed this website ecosystem increment was not considered to be unrealistic given the nominal rate of atmospheric deposition in that area (10 kg ha−1 yr−1) and errors associated with estimates of ecosystem N content. Turner and Lambert (2011) studied a replicated removal (raking)-nutrient addition trial in a radiata pine plantation for 16 years from age 11. All treatments increased in the quantity of nitrogen in the system and the average of the raked (about 32 kg ha−1 yr−1) and unraked plots (about 28 kg ha−1 yr−1) are shown in Table 2. The increases in vegetation and litter are as expected but the overall ecosystem increases exceeded expectations. The studies by Lambert and Turner (2012) at Lidsdale are studies on small catchment. The radiata pine plantation was first sampled when the stand was 42 years old and the same ten plots resampled when the stand was 55 years old with no disturbance. There was an overall increase of 20.4 kg N ha−1 yr−1 of which SP600125 research buy 11.1 was a soil change. Statistically the vegetation and surface soil changes were significant

but the forest floor and deep horizons, while showing increases in N, were not significant. The low productivity native eucalypt catchment had 14 plots resampled over a 34 year period and while the change was smaller (8.5 kg N ha−1 yr−1) it was significant. However, while low in Ketotifen numbers and sparsely distributed there were some N fixing shrubs in the understorey which may account for part of the change. Hopmans and Elms

(2009) used part of the studies on first and second rotation comparisons of radiata pine on deep fine sands in south west Victoria. The soils are naturally nutrient poor. The nutrient stocks had been evaluated in detail at the end of the first rotation and repeated at the end of the second. An accumulation of 4.2 kg ha−1 yr−1 was found. The plantations had no understorey or potential N fixing species present. Guo et al. (2008) compared the N stocks of a sixteen year old P. radiata plantation growing near Canberra to those of adjacent grassland. The plantation had been established on the grassland. They found and overall accumulation of 17.2 kg ha−1 yr−1 over the 16 years but this was a result of accumulation biomass and litter, the soil declined by an average −6.2 kg ha−1 yr−1. The decline in soil early in plantation growth is the expected pattern as N is taken up and accumulated in the biomass. Turner and Lambert (1986) and Turner et al. (2002) (Table 2) reported on two long term phospahtic fertilizer trials in radiata pine plantation on sandstone derived soils. The trials indicated the long term residual effects of applied phosphate and both trials showed long term net accumulation of N in the soil both in the control and untreated plots.